1 STORAGE SYSTEM FOR WATER Technical field [01] This invention relates to liquid storage systems. The invention is particularly suited for storage of rain water, and may also be used for storm water attenuation or grey water storage, or the storage and control of waste water from a building which needs to be later pumped out to a tanker truck for removal. [02] There is a need to make provision for storage of water on building sites. While above ground tanks have been used for this purpose, this is not always possible due to space restrictions. Underground storage tanks require extensive excavation and can be expensive. Background art [03] The patent specification of GB2369400 discloses a water storage system in which water is stored in a series of interconnected tanks in a trench forming part of the foundations of a building. The tanks are as wide as the trench and widely spaced to ensure that there is sufficient load bearing concrete between the tanks. Disclosure of the invention [04] This invention discloses water storage pods suitable for forming an array of water storage pods which are arranged to leave interstices between the pods. [05] According to a first embodiment of the invention there is provided a water storage pod having one or more connection apertures, each aperture being surrounded by a connection flange. [06] According to a further embodiment, the water storage pod includes at least two air connection apertures, each air connection aperture being surrounded by an air connection flange, the pod including at least two water connection apertures, each water connection aperture being surrounded by a water connection flange. [07] Preferably, at least the major upper edges of the pod are rounded.
2 [08] The invention also provides an array of water storage pods, wherein each pod is supported on a support surface and connected to at least one of its adjacent pods via a water connection. [09] Preferably each water connection includes an inner pipe adapted to be a press-fit inside the water connection flanges of the connected pods. [010] The water connection can include an outer sleeve. [011] The outer sleeve and the inner pipe can be of unitary construction. [012] The water connection can include a connection member having first and second end portions and a middle portion, wherein each end portion includes a stub pipe element concentrically surrounded by an outer sleeve defining an annular space therebetween, the annular space being adapted to mate with a water connection flange. [013] The pods can be interconnected by pipes connected to apertures in the bottoms of the pods. [014] Each pod can be connected to at least one adjacent pod via an air connection. [015] The upper and side surfaces of the pods can be encased in concrete to form a slab for a building, the concrete in interstitial spaces between the pods forming support beams for the building. [016] The support surface can be stepped, and the pods on each step can be of differing heights, so that the upper surface presented by the array of pods is substantially at one level. [017] The invention also provides a method of providing a water storage system including providing an array of water storage pods on a surface, the array of pods having interstitial spaces between the pods, interconnecting the pods with water ducts, and filling the interstitial spaces with a flowable, setable material to form a solid interstitial matrix. [018] Preferably adjacent pods are interconnected to enable fluid flow therebetween.
3 [019] The pods may be interconnected by pipes connected to apertures in the bottoms of the pods. [020] Alternatively, the pods may be connected by pipes connected to apertures in the sides of the pods. [021] The pods can be interconnected by pipes to connect the water storage spaces of the pods. [022] The pods can be encased on their upper surfaces and their side surfaces by concrete or a similar flowable, setable material to form a slab structure for a building. [023] The array of pods can be integrated into the structure of a concrete slab, so that the concrete forms a flat surface over the pods and an interstitial matrix surrounding at least the sides of the pods. [024] The concrete filling the interstitial matrix can form a load bearing portion of a concrete floor. [025] The pods can be placed on a surface and the concrete can be poured to enclose and cover the pods. [026] The pods can be interconnected before the concrete is poured. [027] Suitable ducting is provided through the concrete, or an access aperture is left in the concrete to permit water to be fed into or out of the pods. [028] The pods can be interconnected by pipes at or near the lower edge of the or each pod. [029] The pods may have rounded edges to provide a radiused junction line between the slab floor and the concrete in the interstitial matrix. [030] The concrete in the interstices can form support beams. [031] The support surface may be sloped or stepped to facilitate preferential drainage between the pods. Where the pods are of the same height and the support surface is sloping, the 4 thickness of the concrete above the pods may vary. This may be overcome by providing a suitable buffer such as polystyrene pads above the lower pods. [032] The pods may be of differing depths and arranged to facilitate preferential drainage. [033] Where the pods are of differing depths, the support surface can be arranged in a stepped or sloping manner so that the tops can be arranged to be substantially in a horizontal plane, whereby preferential drainage is facilitated. [034] The pods can be interconnected by one or more air pipes at or near the top of each pod. [035] A circulating pump can be provided to circulate the water. [036] The pump can be connected to circulate the water through an aerator. [037] A filter may be located proximate the inlet to the array of pods. [038] A filter may be located proximate the outlet of the array of pods. [039] The water may be passed through a filter while it is being circulated. Brief description of the drawings [040] Figure 1 shows an array of water storage pods in a matrix of concrete. [041] Figure 2 shows a section along line AA-AA of Figure 1. [042] Figure 3 is a schematic illustration of a water storage pod. [043] Figure 4 illustrates the connection of an array of water storage pods to a pump. [044] Figure 5 illustrates an installation of water storage pods on a stepped base. [045] Figure 6 represents resilient expansion sleeve. [046] Figure 7 shows details of a joint between two water storage pods.
5 [047] Figure 8 shows an alternative means of connecting the water storage pods. Description of the invention [048] The invention will now be described with reference to the drawings. [049] In Figure 1, an array of water storage pods 101 are held in a matrix of concrete 102. The interconnections between the water storage pods are not shown in Figure 1. [050] Polystyrene filler blocks 110 or similar filler material may be used to further modify the configuration of the concrete slab. [051] The array of pods may be adapted to suit the load bearing requirements of the building. For example, one or more pods may be omitted from a row, or a whole row may be omitted, or corner pods may be omitted. [052] As shown in Figure 2, a concrete slab 103 covers the water storage pods 101 and concrete also fills the interstices between the water storage pods. The water storage pods 101 are interconnected by a water passage, 104, and an air line 105. [053] A water storage pod is illustrated schematically in Figure 3. The pod is of a basically rectangular or square section or box shaped, with recesses 303 on its vertical faces. Apertures for the water connection 104 and the air connection 105 are located in the recesses and are formed by annular flanges 301 and 302. The water storage pods are made of water proof material, and are preferably made of a plastics material. The water storage pods may be moulded. Preferably the edges and corners are rounded. [054] Figure 4 shows an arrangement for pumping water from the array of water storage pods using a submersible pump. [055] A pump 45 is installed in a pump chamber 43. The bottom of the pump chamber 43 is sufficiently lower than the bottom of the array of water storage pods 101, of which only one is shown, to ensure the pump is submerged. The water storage pod array connects to the pump chamber via a duct 42.
6 [056] Rainwater from the roof enters the array of water storage pods 101 via downpipe 41. The water inlet from downpipe 41 connects to at least one of the pods, and may connect to two or more pods. [057] The connection from the downpipe to the pod may be via the existing water aperture of the pod, which is at the bottom of the pod. In this case, the connection from the downpipe to the pod, at least to the about the top of the pod, should be of a material which is suitable for holding standing water to prevent corrosion. The advantage of this arrangement is that it avoids the necessity to provide a further inlet aperture for the water. [058] Pods around the periphery of the array may be designed with only three water apertures (two for corner units), or the water apertures which are not connected to other pods or to a water inlet may be closed by a suitable watertight closure such as a cap, plug or the like. [059] The pump may be fitted with automatic control such as float controlled switch 46 which may be arranged to switch the pump on when the water reaches a first level 47, and to switch the pump off when the level falls to a second level 48. External controls and the power supply for the pump are supplied via conduit 50. [060] The pump chamber is provided with an overflow outlet 44 which may connect, for example, to the municipal street drainage system, or to a water dispersal grid. The overflow outlet may be at about the same height as the top of the water storage pods 101. [061] The pump 45 may be used to supply the water to a lawn or garden or similar purpose. [062] The pump may alternatively be used to pump the water to an elevated tank. [063] The elevated tank may be higher than the roof gutters. [064] Alternatively, the pump may be used to circulate the water through the array of water storage pods to aerate it and prevent stagnation. [065] Figure 5 shows an array of water storage pods in a stepped array. This arrangement is particularly suited for sloping sites. The surface may be prepared by cutting "steps" 53 into the slope, the steps being suitable for supporting a pod. A left hand pod is shown on the highest step. Because the heights of the pods is thus stepped, the interconnections 104, 105, between 7 the pods needs to be able to accommodate the difference in height. For this reason, flexible interconnections may be used. [066] One feature of the stepped configuration is that the water drains from the upper to the lower pods. [067] Where the pods are on a stepped support surface, the heights of the pods may be varied so that the tops of the pods are substantially at the same level. That is, the tanks may be supplied in different heights, and the steps may be matched to the different pod heights as shown at 52 in Figure 5. [068] Alternatively, the pods may be of the same height and present a stepped upper surface. [069] In a further alternative, the support surface may be built up to present a level upper surface, or filler material may be provided on the top of the pods to produce a level surface. [070] In assembling the pod array, the surface is first prepared by levelling as required. A water resistant layer or membrane may be laid over the support surface and the pod array assembled by interconnecting the water and air lines between the pods. [071] As shown in detail in Figure 7, the annular flanges 301 surrounding the water apertures are interconnected by connection pipe 701 and an outer sleeve 601, both of which provide inner and outer press-fits which are substantially water tight. The connection pipe and/or the outer sleeve may be flexible. The outer sleeve 601 may be a foam expansion sleeve. [072] In a further embodiment, the pipe 701 and the sleeve 601 are formed as an integral unit as shown in Figure 6. [073] In Figure 6, the outer sleeve and the inner pipe are formed of a single piece of material, such as rubber or a suitable substitute. The pipe 701 is concentric with the sleeve 601 and separate therefrom at each end, but the pipe and sleeve are joined in the centre so that there is a blind annulus 604 having a depth indicated by arrow 602 at either end, while the pipe presents a through hole 603. [074] The stub part of the pipe having a length 602 can be inserted inside a flange 301 of a first pod as a press fit while the corresponding part of the outer sleeve is rolled or folded back 8 over the body of the sleeve. The rolled back portion of the sleeve is then unrolled to tightly grasp the outside of the flange 301. The procedure is then repeated with the flange 301 of a second pod. [075] The leading portion of the stub part of the pipe may be slightly tapered to facilitate insertion into the annular flange 301. [076] Similar arrangements may be used for connecting both the water apertures and the air apertures. [077] When the array of pods has been assembled, together with any other formwork, the concrete is poured and flowed around the pods and under and around the interconnecting pipes of the pods. [078] Figure 8 illustrates an alternative embodiment in which the water pipes are connected to an aperture in the bottom surface of the pods. In this case a network of pipes 81, 83, is laid down in trenches provided in the surface, and the pods are connected by downwardly extending pipes 82. The pipes may be connected in a linear array, e.g., pipe 81, or in a two dimensional array as illustrated by pipe 83. A full two dimensional array would include a series of pipes parallel to pipe 81 and a second series of pipes parallel to pipe 83. [079] While the downwardly extending pipe 82 are shown as vertical, it is clearly not essential to the invention that they be vertical. They may be oriented at any suitable angle to permit water to flow out of the pod to the pipe array. [080] The pipe array itself need not be horizontal. The pipes may be laid at any suitable angle, and may be laid to facilitate drainage to a desired location. [081] Of course, configurations other than a square matrix of pods or pipes are possible without departing from the inventive concept. For example: the pods may be hexagonal; the interconnections may be diagonal.
9 Technical applicability [082] The invention enables a large proportion of the sub-floor area of a building to be used as a water storage system. [083] While the invention has been described by way of specific embodiments, the person skilled in the art will understand that the invention can be applied in a various other arrangements and configurations without going beyond the inventive concept.